Simon Thompson is Professor of Logic and Computation in the Computing Laboratory of the University of Kent, where he has taught computing at undergraduate and postgraduate levels for the past twenty five years, where he was department head 2002-2009.

His research work has centered on functional programming: program verification, type systems, and most recently development of software tools for functional programming languages. His team has built the HaRe tool for refactoring Haskell programs, and is currently developing Wrangler to do the same for Erlang. His research has been funded by various agencies including EPSRC and the European Framework programme. His training is as a mathematician: he has an MA in Mathematics from Cambridge and a D.Phil. in mathematical logic from Oxford.

He has written four books in his field of interest; Type Theory and Functional Programming published in 1991; Miranda: The Craft of Functional Programming (1995), Haskell: The Craft of Functional Programming (3rd ed. 2011) and Erlang Programming (with Francesco Cesarini, 2009). Apart from the last, which is published by O'Reilly, these are all published by Addison Wesley.

Writing EUnit tests is more common than writing QuickCheck specifications, although QuickCheck specifications potentially explore far more scenarios than manually written unit tests. In particular for implementations that have side-effects, writing a good set of EUnit tests is often difficult and labour intensive.

In this tutorial we explain a mechanism to extract QuickCheck specifications from EUnit test suites. We use the QSM algorithm to infer state machines from sets of positive and negative traces derived from the test suite. These traces can be derived either statically or dynamically and we describe both approaches here. Finally we show how to move from the inferred state machine to a QuickCheck state machine. This QuickCheck state machine can then be used to generate tests, which include the EUnit tests, but also include many new and different combinations that can augment the test suite. In this way, one can achieve substantially better testing with little extra work.

We'll show the method in action with a test-driven development example, and encourage you to try the method out too. Please bring your own EUnit test suit to play with and see the results.

Tutorial: DIY Refactoring in Wrangler

Wrangler is an Erlang refactoring tool which provides a range of refactorings - including renaming, function extraction and generalisation - as well as facilities for clone detection and removal as well as improvement of the module structure of projects. Wrangler is integrated into emacs and Eclipse (via ErlIDE).

Up to now, you could only use the refactorings built into Wrangler, or dive deep into the internals to extend it. The latest version of Wrangler now provides a much easier way of defining and applying refactorings for yourself. All you need to do is implement them as a refactoring behaviour and they are accessible in emacs, and you can write descriptions of what the refactorings do using a combination of Erlang macros and templates that describe the particular changes to be made. You can also use the same facilities write new forms of code inspection equally easily.

As well as being able to write new refactorings from scratch, we're providing a scripting language in which you can build complex refactorings by putting together simpler components: this can, for example, provide a mechanism for migrating from an old to a new API, or for transforming the data type forming the input/output of a collection of functions.

After giving an overview of the DIY facilities we'll help you to get started writing your own refactorings and scripts.